1. Field of the Invention
The present invention relates to vertically mountable semiconductor device packages. More specifically, the present invention relates to minimally packaged semiconductor devices which are vertically attached to a carrier substrate. Preferably, the present invention also relates to user-upgradable surface mount packages.
2. Background of Related Art
Vertical surface mount packages are known in the art. When compared with traditional, horizontally mountable semiconductor device packages and horizontally oriented multi-chip packages, many vertical surface mount packages consume less area on a circuit board or other carrier substrate than a horizontally mounted package of the same size. Many vertical surface mount packages may also have a superior ability to transfer heat than conventional horizontally mountable semiconductor device packages and horizontally oriented multi-chip packages. Thus, the semiconductor industry is finding that vertical surface mount packages offer advantages over their traditional, horizontally mountable counterparts.
Various vertical surface mount packages are disclosed in U.S. Pat. No. Re. 34,794 (the "'794 patent"), issued to Warren M. Farnworth on Nov. 22, 1994; U.S. Pat. No. 5,444,304 (the "'304 patent"), issued to Kouija Hara and Jun Tanabe on Aug. 22, 1995; U.S. Pat. No. 5,450,289, issued to Yooung D. Kweon and Min C. An on Sep. 12, 1995; U.S. Pat. No. 5,451,815, issued to Norio Taniguchi et al. on Sep. 19, 1995; U.S. Pat. No. 5,592,019, issued to Tetsuya Ueda et al. on Jan. 7, 1997; and U.S. Pat. No. 5,635,760, issued to Toru Ishikawa on Jun. 3, 1997.
Some designs of vertical surface mount packages include wire bonded leads to operatively connect a semiconductor device to a circuit board which tend to increase the inductance and decrease the overall speed with which the device conducts electrical signals. The use of permanent wire bonds is necessary to electrically connect many such semiconductor devices to the circuit boards while the semiconductor devices are typically adhesively attached to the circuit board to be supported thereon, thereby preventing the vertical surface mount package from being readily user-upgradable.
Electrical connections may also be made between many types of electronic devices and a circuit board by means of sockets. For example, sockets are commonly employed to establish and maintain an electrical connection between a mother board and a daughter board, such as a single in-line memory module (SIMM). Exemplary devices are found in the following U.S. Pat. No. 4,781,612, issued to Roger L. Thrush on Nov. 1, 1998; U.S. Pat. No. 4,995,825, issued to Iosif Korsunsky et al. on Feb. 26, 1991; U.S. Pat. No. 5,209,675, issued to Iosif Korsunsky on May 11, 1993; U.S. Pat. No. 5,244,403, issued to Gregory J. Smith et al. on Sep. 14, 1993; and U.S. Pat. No. 5,256,078, issued to Nai H. Lwee and David J. Dutkowsky on Oct. 26, 1993. Each of the foregoing patents discloses the use of contacts within the socket which resiliently engage contacts on the daughter board to establish an electrical connection between the daughter board and the mother board.
However, none of those devices disclose the use of a socket for removably mounting a minimally packaged semiconductor device to a circuit board. The circuitry of a daughter board and the typical use of wire bonding to attach a semiconductor device thereto each tend to increase the inductance of such devices. Some socket-mountable daughter boards include more than one semiconductor device permanently attached thereto. Thus, such devices are not readily user-upgradable.
What is needed is a low impedance, vertically mountable semiconductor device package which has improved heat transferability and is readily user-upgradable.